Conventionally, AC transmission systems have been widely used to transmit power.
However, when AC transmission is used for long-distance power transmission, a great power transmission loss is caused, and therefore DC power transmission systems are sometimes used for long-distance power transmission.
As cables (DC power cables) for DC power transmission systems, oil-filled isolated cables have been widely used.
However, oil-filled isolated cables require regular maintenance of booster pumps and the like in order to keep insulating oil in the cables. When the insulating oil is flowed out, an influence on the environment will be problematic.
To overcome this, a DC power cable including an insulating layer made of an insulating resin composition is disclosed as a DC power cable that is easy to maintain and has no risk of oil leakage (see PTL 1 below).